JP4850261B2 - Butt double-sided submerged arc welding method for shear-cut steel plate - Google Patents

Description

  The present invention relates to a butt double-sided submerged arc welding method for shear-cut steel plates, in which the edges of shear-cut steel plates are butt-welded.

  In Patent Document 1, when a Y-shaped groove is formed on a thick steel plate and butt welding is performed on one side, in order to improve the bead failure due to the root interval formed on the back surface, the groove space from the groove portion to the root space on the back surface is disclosed. To achieve this, a technique for filling and welding a cut wire is disclosed.

Japanese Patent Laid-Open No. 9-267175

  However, in Patent Document 1, a sufficient penetration depth is ensured using four electrodes, and a bead is applied to the back surface. There are problems such as requiring time and accuracy in the forming process and causing the cost to increase.

  Therefore, the present inventors considered cost reduction by directly welding the mill edge of the steel sheet without the groove forming step. However, in the case of a large rolled steel plate having a thickness of 50 mm or less, for example, the mill edge is cut by a shear cutting machine, and its cross section is formed into a unique cross section with unevenness. Irregular route intervals are formed.

  In addition, since a large welding depth cannot be secured with a small welding facility, a steel plate with a large thickness is reversed and double-sided welding is performed. However, in this double-sided welding, the smaller the number of reversals, the shorter the work time and cost. it can.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a butt double-sided submerged arc welding method for shear-cut steel sheets that can easily and satisfactorily weld shear-cut edges with irregular root intervals.

The invention described in claim 1
When welding both sides of the shear cutting edge of a steel plate whose edge has been cut by a shear cutting machine,
On the surface plate, the cut wire is arranged along the planned welding line, and the pair of steel plates are opposed to both sides with the shear cutting edges sandwiching the planned welding line, or on the welding planned line and outside thereof. Arranged to be
Both of the pair of steel plates are brought close to each other, or the steel plates arranged on the outside are brought close to the steel plate on the planned welding line, and the cut wire is sandwiched and filled in the root space between the shear cutting edges,
After replenishing or removing the cut wire in the root space and leveling the height uniformly, surface welding is performed,
After reversing the steel sheet, a cut wire is replenished in the root space and its height is uniformly leveled, and then back surface welding is performed.

According to a second aspect of the present invention, in the configuration of the first aspect,
The thickness of the steel sheet is 8 mm or more and 20 mm or less,
In the case where the back surface route interval between shear cutting edges exceeds 7 mm, the contact portion of the shear cutting edge is polished or welded to the portion of the back surface route interval to 7 mm or less.

Furthermore, the invention according to claim 3 is the configuration according to claim 1 or 2,
Place the cut wire on the surface plate with the top raised to at least the plate thickness center level of the steel plate,
The top of the cut wire before surface welding
When the route interval on the back surface is less than 5 mm, it is leveled to the range from the surface level of the steel plate to the plate thickness center level of 1/2 the plate thickness of the steel plate,
If the distance between the roots of the back surface is 5 mm or more, the surface level of the steel plate is leveled to the range of 2 mm from the back side,
The top of the cut wire before back surface welding is leveled to a range of 2 mm from the back surface level to the front surface side of the steel sheet.

The invention according to claim 4 is the configuration according to any one of claims 1 to 3,
The section of the shear cutting edge has a top portion that protrudes toward the shear cutting edge side of the steel sheet to be abutted at a position close to the surface,
In the state where the root distance of the surface is narrower by the top, surface welding is performed,
Back surface welding is performed in a state where the route interval on the back surface is wider than the route interval on the front surface.

  According to the first aspect of the present invention, the cut wire placed on the surface plate is sandwiched between the shear cutting edges of the steel plate, so that the uneven root space can be filled uniformly and effectively. Surface welding can be performed with a sufficient amount of weld metal using a cut wire. Moreover, the reverse surface welding after reversal can be performed with a sufficient amount of weld metal by a cut wire, and the steel sheet can be welded with a sufficient penetration depth and bonding strength without welding defects such as blowholes and meltdown. In addition, the number of inversions is set to one, and no chipping process by gouging is required, so that work time and cost can be reduced.

  According to the invention described in claim 2, by setting the root interval of the back surface of the steel plate having a thickness of 8 to 20 mm to 7 mm or less, there is no welding defect such as blow hole or melt-down, and butt double-side welding of the shear cutting edge. Can be performed satisfactorily.

  According to the third aspect of the invention, the upper surface of the cut wire in the route space is leveled to a predetermined range corresponding to the route interval on the back surface. Welding defects such as irregularities can be prevented.

  According to the invention described in claim 4, since the back surface of the steel plate is used as the upper surface so that the root interval of the back surface is widened before the back surface welding after the reversal at the butt welding of the shear cutting edge, the cut wire dropped during the reversal. Can be replenished easily, leveling can be performed accurately, and back surface welding can be performed satisfactorily.

(A)-(e) is sectional drawing explaining embodiment of the butt double-sided submerged arc welding method of the shear cut steel plate based on this invention, (a) (b) is a cut wire filling process, (c) is a surface. A welding process, (d) shows a reversal, a cut wire supplement process, and (e) shows a back surface welding process. (A)-(d) is the principal part expanded sectional view of FIG. 1, (a) is a cut wire filling process, (b) is a surface welding process, (c) is inversion, a cut wire replenishment process, (d) is A back surface welding process is shown. (A) And (b) is operation | movement explanatory drawing of a cut wire filling process, (a) shows before filling, (b) shows after filling. (A) And (b) is a principal part expanded sectional view explaining Example 2 of a cut wire filling process, (a) shows before filling and (b) shows after filling. It is a principal part expanded sectional view explaining Example 3 of a cut wire filling process. (A)-(c) is an expanded sectional view of a shear cutting edge, (a) is the 1st example of an edge, (b) is the 2nd example of an edge, (c) shows the butt | matching state of a 1st example. (A)-(e) is a principal part expanded cross section explaining the I groove | channel butt double-side welding method of a comparative example, (a) is a sealing bead formation process, (b) is a cut wire filling process, (c) is surface A welding process, (d) shows a chipping process, and (e) shows a back surface welding process.

(Comparative example)
First, as a comparative example, a procedure in the case of performing double-sided welding with a steel sheet having an I-groove formed at the edge and filling the root space with a cut wire will be described with reference to FIG.

1. The surfaces of the steel plates 1 and 1 are arranged on the surface plate upward, and the sealing beads 3 are formed in the root space of the surface by welding. [FIG. 7 (a) Sealing bead formation process]
2. After reversing the steel plates 1, 1, the cut wire 2 is filled into the root space. [Figure 7 (b) Cut wire filling process]
3. Surface beads 4 are formed by surface welding with a sufficient penetration depth. [Fig. 7 (c) Surface welding process]
4). After reversing the steel plates 1 and 1, the rear surface chip 5 is performed by gouging and the sealing bead 3 is deleted. [Fig. 7 (d) Deburring process]
5). The back surface bead 6 is formed by welding the back surface with a sufficient penetration depth from the back surface chip 5. [Fig. 7 (e) Back surface welding process]
According to the above comparative example, both the front bead 4 and the back bead 6 were able to ensure sufficient penetration depth, bead width, and sufficient strength, and no weld defects were seen.

  By the way, in the case of a large-sized rolled steel sheet, generally, a steel sheet having a thickness of 50 mm or less is shear-cut at the edge, and the dimensions thereof are aligned, as shown in FIGS. 6 (a) and 6 (b). , A unique cross-sectional shape. A step portion is also formed at the seam of the shear cutting portion.

Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 3 and FIG.
(Shear cutting edge)
As shown in FIGS. 1 and 2, on the upper surface of the surface plate 10, the height position of the steel plate 11 is set, and a plurality of guide members 12 having a predetermined height for guiding the movement are parallel to the planned welding line WL. Projected. The plate thickness t of these steel plates 11 is preferably 8 mm to 20 mm.

As shown in FIG. 6, the shear cutting edge 13 of the steel plate 11 protrudes from the front surface to the rear surface side with a small sloped surface inclined portion Q and the shear cutting edge 13 side of the steel plate 11 to be abutted at a position approaching the surface. There is a case in which a top portion R and a back inclined portion S that is inclined to the inner side of the back surface, and a concave portion T is formed in the back inclined portion S. For example, as a result of actually measuring a plurality of large rolled steel sheets having a thickness of 17 mm, a width of 2000 mm, and a length of 12000 mm, σ1 = 1.4 to 2.0 mm, σ2 = 0.1 to 1.2 mm, and shear The cut seam was also found to be less than 2.0 mm.

  As a result, when the shear cutting edge 13 is attached, a route interval G of the intermediate portion that is maximum when the concave portion T is present, a route interval Ga on the front surface, and a route interval Gb on the back surface are formed. In addition, the cross section of the shear cutting edge 13 changes along the length direction. However, when the root interval Gb on the back surface when the shear cutting edge 13 is abutted exceeds 7 mm, defects such as burnout and blowholes are caused. Many are expected to occur. If the root gap Gb on the back surface exceeds 7 mm when the shear cutting edge 13 of the steel plate 11 is abutted here, the contact portion of the shear cutting edge 13 is previously removed with a polishing tool, or the maximum root interval portion Must be preliminarily welded and the root distance Gb on the back surface should be 7 mm or less. Even if the route interval G in the intermediate portion is wider than the route interval Gb on the back surface and exceeds 7 mm, it is not necessary to perform overlay welding. This is because, as will be described later, by filling the root space 14 exceeding 7 mm with the cut wire 15 to a thickness of 1/2 or more of the plate thickness t, it is possible to prevent burnout during welding.

  The cut wire 15 that fills the root space 14 between the shear cutting edges 13 is the same component as the welding wire for submerged arc welding of the steel plate 11, and the one that is cut with the same length as the diameter is used. For example, one having a diameter of 1 mm and a length of 1 mm is used.

(Welding process)
The welding process of the large steel plate 11 will be described with reference to FIGS.
A. Cut wire filling process a. A pair of steel plates 11 are arranged on the surface plate 10 with a predetermined interval so that the surface thereof is an upper surface and the shear cutting edges 13 are opposed to each other on both sides of the planned welding line WL. Here, since the surface of the steel plate 11 is the upper surface, the top portions R are close to each other in the butting state, and the route interval Ga on the surface is narrower than the route interval Gb on the back surface. [See Fig. 6 (c)]
b. On the surface plate 10, along the planned welding line WL between the shear cutting edges 13, the top of the cut wire 15 is at least higher than the plate thickness center level CL at 1/2 the plate thickness of the steel plate 11: t. Raise and arrange. [See FIG. 1 (a) and FIG. 3 (a)]
c. The pair of steel plates 11 are brought close to each other, and the cut wire 15 is sandwiched and filled in the root space 14 of the shear cutting edge 13. In this contact or proximity state, the route interval Gb on the back surface is at least 7 mm or less. [Refer to FIG. 1 (b) and FIG. 3 (b)] Further, the cut wire 15 that protrudes from the surface route space Ga to the surface of the steel plate 11 is removed and the cut wire 15 that is insufficient in the route space 14 is replenished. [See FIG. 2 (a)]
Here, when the route interval Gb on the back surface is less than 5 mm, the upper surface level TL of the cut wire 15 is evenly distributed so as to be in the range from the surface level SL of the steel plate 11 to the plate thickness center level CL. This is because if the upper surface level TL of the cut wire 15 is less than the plate thickness center level CL, the surplus height is insufficient, and if it exceeds the surface level SL, it becomes difficult to uniformly disperse, and welding This is because the amount of metal is not constant, and there is a problem that irregularity of the weld bead is caused.

Further, when the root distance Gb on the back surface is 5 mm or more, the upper surface level TL of the cut wire 15 is equalized so that the surface level SL of the steel plate 11 is within the range of 2 mm from the surface level SL to the back surface side. This is because if the cut wire 15 is less than 2 mm from the top surface to the back surface side, the surplus height is insufficient or drops off, and if the surface level SL is exceeded, it can be uniformly distributed. This is because the amount of the weld metal is not constant and the surface bead 16 becomes irregular. [See FIG. 2 (a)]
Here, even if the route interval G in the intermediate portion is larger than 7 mm which is the route interval Gb on the back surface, the cut wire 15 is filled in the range from the surface level SL to the plate thickness center level CL of the steel plate 11 and evenly distributed. By doing so, it is possible to prevent burnout during welding.

B. Surface welding process Surface welding is performed by submerged arc welding to form a surface bead 16 having a sufficient penetration depth from the surface inclined portion Q to the intermediate portion of the back inclined portion S through the top portion R. The welding current in surface welding is, for example, 700 to 750 Amp, welding voltage 38 to 42 Volt, and welding speed 40 to 42 cm / min. [Refer to FIG. 1 (c), FIG. 2 (b)]
C. Inversion, cut wire replenishment step The steel plate 11 is lifted and inverted. Further, the cut space 15 is replenished in the route space 14 using the route interval Gb on the back surface wider than the route interval Ga on the front surface, and the surface is evenly leveled. The upper surface level UL of the cut wire 15 at this time is in a range from the rear surface level BL to 2 mm on the front surface side. Here, when the upper surface level UL of the cut wire 15 is less than 2 mm on the front surface side, the surplus height is insufficient, and when the upper surface level UL exceeds the rear surface level BL, it becomes difficult to uniformly disperse, and welding is performed. This is because the amount of metal is not constant, causing irregularities in the back surface bead 17. [See FIG. 1 (d) and FIG. 2 (c)]
D. Back surface welding process Back surface welding is performed by submerged arc welding, and the back surface bead 18 having a sufficient penetration depth from the back surface to the back inclined portion S is formed. The welding current in back surface welding is, for example, 800 to 830 Amp, welding voltage 38 to 42 Volt, and welding speed 36 to 42 cm / min. [Refer to FIG. 1 (e) and FIG. 2 (d)]
According to the first embodiment, the cut wires 15 arranged on the surface plate 10 are sandwiched between the opposed shear cutting edges 13, so that the cut wires 15 are evenly and uniformly disposed in the uneven root space 14 of the shear cutting edges 13. It can be filled effectively. Therefore, the surface bead 16 can be formed by melting a sufficient amount of weld metal composed of the cut wire 15 and the welding wire to a sufficient depth by surface welding. Moreover, the back surface bead 17 which reaches the surface bead 16 can be formed by melting a sufficient amount of the weld metal composed of the cut wire 15 and the welding wire to a sufficient depth by the back surface welding after the reversal. Therefore, the steel plate 11 can be welded with sufficient joining strength without welding defects such as blowholes and burnout by a small welding facility. Further, compared with the double-sided butt welding of the I groove of the comparative example, the number of inversions of the steel plate 11 is as small as one, the sealing bead 4 is not formed, and the chipping process can be eliminated, thereby reducing the cost. Can do.

  Further, the upper surface TL, UL of the cut wire 15 in the route space 14 is leveled to a predetermined range corresponding to the route interval Gb on the back surface, thereby adjusting the weld metal amount to an appropriate amount, It is possible to prevent welding defects such as occurrence of dropout and irregular weld beads.

  Furthermore, since the steel plate 11 is arranged so that the root interval Gb on the back surface is widened when the shear cutting edge 13 is abutted, the cut wire 15 that has dropped at the time of reversal can be easily and accurately replenished in the root space 14. it can.

(Example 2 of cut wire filling process)
Next, another embodiment 2 of the cut wire filling process will be described with reference to FIG.
d. On the surface plate 10, along the planned welding line WL of the shear cutting edge 13, the cut wire 15 is arranged so that its top is at least higher than the plate thickness center level CL of the steel plate 11.

  e. One steel plate 11 whose surface is the upper surface is disposed at a position where the shear cutting edge 13 corresponds to the top of the cut wire 15 above the planned welding line WL, and is further lowered onto the surface plate 10. Thereby, the shear cutting edge 13 of one steel plate 11 is covered with the cut wire 15 at most of the shear cutting edge 13 including at least the plate thickness center level CL.

f. The other steel plate 11 whose surface is the upper surface is disposed on the surface plate 10 outside the planned welding line WL so that the shear cutting edges 13 face each other. [See FIG. 4 (a)]
g. The other steel plate 11 is brought close to the one steel plate 11 to fill the root space 14 of the shear cutting edge 13 with the cut wire 15. (Hereafter, the upper surface level TL of the cut wire 15 is leveled as in the cut wire filling step c.) [Refer to FIG. 4B]
According to another embodiment 2 of the cut wire filling step, the same operational effects as in the previous embodiment can be achieved.

(Example 3 of cutting wire filling process)
Next, another embodiment 3 of the cut wire filling process will be described with reference to FIG.
h. A pair of steel plates 11 whose surfaces are upper surfaces are arranged on the surface plate 10 so that the shear cutting edges 13 face each other on both sides of the planned welding line WL.

i. On the surface plate 10, along the shear cutting edge 13 of one steel plate 11, the cut wire 15 is arranged so as to be raised so that the top thereof is at least higher than the plate thickness center level CL.
j. The other steel plate 11 is brought close to one steel plate 11, the cut wire 15 is sandwiched between the shear cutting edges 13, and the root space 14 is filled. (Hereafter, the upper surface level TL of the cut wire 15 is leveled as in the cut wire filling step c.)
According to another embodiment 3 of the cut wire filling step, the same operational effects as in the previous embodiment can be obtained.

10 Surface plate 11 Steel plate 12 Guide member 13 Shear cutting edge 14 Root space 15 Cut wire 16 Front bead 17 Back bead R Top Gb Route distance on the back

Claims (4)

When welding both sides of the shear cutting edge of a steel plate whose edge has been cut by a shear cutting machine,
On the surface plate, the cut wire is arranged along the planned welding line, and the pair of steel plates are opposed to both sides with the shear cutting edges sandwiching the planned welding line, or on the welding planned line and outside thereof. Arranged to be
Both of the pair of steel plates are brought close to each other, or the steel plates arranged on the outside are brought close to the steel plate on the planned welding line, and the cut wire is sandwiched and filled in the root space between the shear cutting edges,
After replenishing or removing the cut wire in the root space and leveling the height uniformly, surface welding is performed,
A method of butt double-sided submerged arc welding of shear-cut steel plates, characterized in that after the steel plates are reversed, the cut wires are replenished in the root space and the heights are uniformly leveled, and then the back surface welding is performed. The thickness of the steel sheet is 8 mm or more and 20 mm or less,
When the back surface root interval between shear cutting edges exceeds 7 mm, the contact portion of the shear cutting edge is polished or welded to the portion of the back surface root interval to 7 mm or less. A butt double-sided submerged arc welding method for shear-cut steel plates according to claim 1. Place the cut wire on the surface plate with the top raised to at least the plate thickness center level of the steel plate,
The top of the cut wire before surface welding
When the route interval on the back surface is less than 5 mm, it is leveled to the range from the surface level of the steel plate to the plate thickness center level of 1/2 the plate thickness of the steel plate,
If the distance between the roots of the back surface is 5 mm or more, the surface level of the steel plate is leveled to the range of 2 mm from the back side,
The butt double-sided submerged arc welding method for shear-cut steel plate according to claim 1 or 2, wherein the top of the cut wire before back surface welding is leveled to a range of 2 mm from the back surface level to the front surface side of the steel plate. The section of the shear cutting edge has a top portion that protrudes toward the shear cutting edge side of the steel sheet to be abutted at a position close to the surface,
In the state where the root distance of the surface is narrower by the top, surface welding is performed,
4. The butt double-sided submerged arc welding method for shear-cut steel sheets according to claim 1, wherein the back surface welding is performed in a state where the back surface route interval is wider than the front surface route interval.

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